1. Field of the Invention
The present invention relates generally to semiconductors and, more particularly, to power metal-oxide-semiconductor transistors and methods of fabricating and using same.
2. Description of Related Art
A lateral double-diffused metal-oxide-semiconductor (LDMOS) field effect transistor (MOSFET) is a MOSFET fabricated with coplanar drain and source regions. LDMOS devices with a P-channel may be referred to as LDPMOS devices. These devices are typically used in high voltage applications. When designing such LDPMOS devices, it is important for the device to have a very high breakdown voltage (BVD) whilst also exhibiting, during operation, a low specific on-resistance (Ronsp). By designing LDPMOS devices with low Ronsp and high BVD, low power loss can be achieved in high voltage applications. In addition, a low Ronsp can facilitate a high drain current (Idsat) when the transistor is in saturation. One problem encountered when designing such LDPMOS devices is that approaches tending to maximize BVD tend also adversely to affect the Ronsp and vice versa. In other words, a trade-off (e.g., inverse relationship) is typically presented between the optimization of BVD and Ronsp.
A need thus exists in the prior art for a lateral power MOSFET arrangement that can provide an effective compromise between large BVD and small Ronsp.